Grounding pads, also known as electromagnetic interference (EMI) gaskets, are used in a variety of applications in which electromagnetic radiation can interfere in the operation of an electrical device, e.g., a cell phone, television, monitor or the like. These pads typically comprise an electrical conductor, e.g., copper foil, with means of joining the conductor to one or more electrical components within the device in which it, i.e., the pad, is located. These means include mechanical fasteners, welds, solder and conductive adhesives. Some pads also require a compressive feature, e.g., foam, so that they will conform to the space into which they are fitted, e.g., within the confines of a cell phone.
FIG. 1 is a schematic drawing of one such pad. Grounding pad 10 comprises copper conductor 11 folded into a Z-shape configuration. Top horizontal leg or layer 11a is electrically connected with bottom horizontal leg or layer 11c by diagonal leg 11b. In the space between conductor legs 11a and 11b is compressible foam 12a, and in the space between conductor legs 11b and 11c is compressible foam 12b. The foam may or may not be electrically conductive. On the external facial surfaces of conductor legs 11a and 11c is optional adhesive 13a and 13b, respectively. The adhesive is typically a pressure sensitive adhesive (PSA), and it is typically electrically conductive. In operation typically one horizontal leg of the Z-folded conductor is attached by the PSA to an electrically conductive shield while the other horizontal leg of the Z-folded conductor is attached by the PSA to an electrical ground, e.g., a ground trace of a printed circuit board. Alternatively, conductor legs 11a and 11c can attach to the shield and ground, respectively, by other means, e.g., weld, solder, mechanical fastener and the like. In the presence of electromagnetic radiation, e.g., static electricity, electrical current is captured by the shield and directed through the Z-folded conductor to the ground thus protecting the device in which the pad is located from damage.
While functional, current pads with a Z-shape folded conductor are difficult and expensive to manufacture. Foam is difficult to insert into the spaces between the legs of the folded conductor, and the connecting diagonal leg adds to the cost of manufacture. Accordingly, grounding pads with more cost effective designs and manufacturing processes are of interest to the various industries in which grounding pads are used.